Objective: to compare the chairside time of fixed mandibular retainers
when bonded using the conventional direct technique and the 3D printed positioning tray.
Methods: A randomized clinical trial was performed using the two techniques to directly and
indirectly bond the fixed lingual retainers, 20 subjects who in need of fixed retainers showing no
signs of enamel defects or signs of gingival inflammation were recruited in this study. 20 retainers
were bonded to the lower anterior teeth. Group I was the intervention group (3D positioning tray
technique) and Group II was the comparative (the direct technique). In the intervention group,
lower impression was taken and the cast produced was scanned using desktop scanner to produce
the digital model on which the virtual retainer was placed using the OrthoAnalyzer software. The
tray was designed by using Appliance Designer software and printed with rigid resin to allow ease
of insertion and removal. The wire was placed inside the 3D positioning tray and then transferred
inside the patients mouth the chairside time was recorded ,In the comparative group, same steps
where done as intervention group, but with the exception of the bonding technique where the
retainer was placed directly inside the patients mouth.
Results: the Chairside time in group I (3D printed positioner) was (15:35 ± 0.03) minutes while in group II
(Control) was (17:52 ± 0.05) minutes.
Conclusion: The chairside time difference between the two bonding techniques was statistically
significant, with the 3D positioning tray technique taking less chairside time than direct technique.